Ireland's Catholic clergy must admit to "abominable acts" over the child abuse scandal that rocked the church in the Republic, a Vatican official said today.

The warning came hours before Irish bishops were due to meet the pope for talks about the scandal.

The call for Irish clergy to own up to their responsibilities over the abuse was made at a mass in St Peter's Basilica shortly before the bishops began two days of discussions with the pontiff.

"Yes, storms spark fear – even those that rock the boat of the church because of the sins of its members," the Vatican secretary of state, Cardinal Tarcisio Bertone, said.

Bertone said trials within the church "are naturally harder and more humiliating", particularly when "men of the church were involved in such particularly abominable acts".

The meetings, which began early today, were described by the primate of All Ireland, Cardinal Sean Brady, as "one step in a process ... which will lead to a journey of repentance, renewal and reconciliation".

Each Irish bishop is expected to speak with the pope for about seven minutes.

Brady said that process "hopefully, will gain momentum when we get back to Ireland".

Yesterday the bishop of Clogher, Joseph Duffy, said he and his colleagues had "a responsibility to be as frank and as open and as candid as is possible" about child sex abuse by clergy and institutional abuse.

Bishop Duffy, the chairman of the communications commission of the Irish Bishops' Conference, said the meetings were "not just a cosmetic exercise".

"They are serious," he added, saying it would be "a complete flop" if the meetings were "seen as a formality or a glossing over of difficult points", he said.

He said he and his fellow bishops would "be keeping survivors at the top of the list of priorities" in addressing the pontiff and the curial cardinals.

Each bishop had been invited "to account directly to the holy father", he added, and referred to "the failure of all of us, including bishops, for not doing what we were expected to do".

Duffy agreed that there had been "tensions" among the bishops over the fallout from the Murphy report into the child abuse scandal, but said that "to describe them as divisions is another matter".